Commit-ID: 61bccf191fe2d55b8d003b4ea3f94913745aaefa
Gitweb: http://git.kernel.org/tip/61bccf191fe2d55b8d003b4ea3f94913745aaefa
Author: Robert Richter <robert.richter@xxxxxxx>
AuthorDate: Wed, 22 Aug 2012 09:23:51 +0200
Committer: Robert Richter <robert.richter@xxxxxxx>
CommitDate: Mon, 27 Aug 2012 14:49:39 +0200
oprofile: Remove 'WQ on CPUx, prefer CPUy' warning
Under certain workloads we see the following warnings:
WQ on CPU0, prefer CPU1
WQ on CPU0, prefer CPU2
WQ on CPU0, prefer CPU3
It warns the user that the wq to access a per-cpu buffers runs not on
the same cpu. This happens if the wq is rescheduled on a different cpu
than where the buffer is located. This was probably implemented to
detect performance issues. Not sure if there actually is one as the
buffers are copied to a single buffer anyway which should be the
actual bottleneck.
We wont change WQ implementation. Since a user can do nothing the
warning is pointless. Removing it.
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Signed-off-by: Robert Richter <robert.richter@xxxxxxx>
---
drivers/oprofile/cpu_buffer.c | 11 +++--------
1 files changed, 3 insertions(+), 8 deletions(-)
diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c
index b8ef8dd..8aa73fa 100644
--- a/drivers/oprofile/cpu_buffer.c
+++ b/drivers/oprofile/cpu_buffer.c
@@ -451,14 +451,9 @@ static void wq_sync_buffer(struct work_struct *work)
{
struct oprofile_cpu_buffer *b =
container_of(work, struct oprofile_cpu_buffer, work.work);
- if (b->cpu != smp_processor_id()) {
- printk(KERN_DEBUG "WQ on CPU%d, prefer CPU%d\n",
- smp_processor_id(), b->cpu);
-
- if (!cpu_online(b->cpu)) {
- cancel_delayed_work(&b->work);
- return;
- }
+ if (b->cpu != smp_processor_id() && !cpu_online(b->cpu)) {
+ cancel_delayed_work(&b->work);
+ return;
}
sync_buffer(b->cpu);
--
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